Manufacture of inner tubes



A g- 1929- G. L. MATHER 2 MANUFACTURE OF INNER TUBES Filed Nov. 2'7, 1926 2 Sheets-Sheet l George L- Malh r In Pen far I 77 AfForne 2 Sheets-Sheet 2 4 i W @h m Q. L. v x $52 a .2 2 I v W mk w AH-arm Aug. 6, 1929. G. L. MATHER MANUFACTURE OF INNER TUBES Filed Nov. 27, 1926 Patented Aug. 6, 1929.

1,723,571 [UNITED STATES PATENT- OFFICE- GEORGE L. MATHER, F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE FISK RUBBER COMPANY, OF CHICOPEE FALLS, MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS.

MANUFACTURE OF INNER TUBES.

Application filed November 27, 1926. Serial No. 151,094.

My invention relates to the manufacture of rubber tubes, such as inner tubes for pneumatic tire casings and more particularly to a method and means forforming such tubesin annular form for curing in an annular mold.

It is among the objects of my invention to provide a method of forming annular tubes from a fiat sheet of suitable stock and to provide a device which will automatically form a fiat band of such stock into an annular tube. Other and further objects will be apparent from the following specification and claims.

In the accompanying drawings which illustrate one embodiment of my invention,

Figure 1 is a plan view of my device,

Figure 2 is. a side elevation of the same, partly in section, 1

Figure 3 is a section substantially on line 3-3 of Figure 1, but on a larger'scale,

Figure 4 is a section showing the initial step in shaping the tube,

Figure 5 is a section showing a succeeding stepin forming the tube, r Figure 6 is a detail of a cutter for forming the hole to receive the valve.

v Figure 7 is a fragmentary perspective view showing the manner in which the cutter of Figure 6 engages the tube, and

Figure 8 is a detail of the toggle for expanding the clamping ring.

Referring to the drawings 1 designates a spider shaped base which is provided with upstanding members 2 adapted to support an annular vacuum shaping box 3. The latter is formed with an annular U shaped cavity 4 the walls of which are provided with a plurality of perforations 5 communicating with the vacuum chamber 6 adapted to be connected as at 7, through a three-way valve 8, to a suitable source of fluid exhaustion not shown, or to be vented to the atmosphere through vent 9. Perforations 5 are connected together by means of grooves 10 formed'on the inner face of the cavity 4.

Slidably engaging the inner periphery of the vacuum box 3 are two cylindrical members 12 and 13, normally positioned, as shown in Fi ure 2 at either side of the cav- "ty 4 and adapted When'moved together to close said cavity. Preferably packing rings 11 are provided between members 12-- 13 andthe base of box Members 12 and 13 are adapted to be simultaneously moved toward each other by means, best shown in 1" Figures 1 and 3. These means comprise r ngs 15 and 16 supported respectively in v guidewaysl'? and 18, the former formed in, blocks 19 supported on the top face of the vacuum box and the latter formed in members 2. These rlngs are provided with gear segments 20 and 21 respectively engaging gears 22 and 23 carried by a vertical shaft 24 mounted inia bearing 25 secured to the outer periphery of the vacuum box. Shaft 24 is provided at its upper end with a hand wheel 26. on the inner periphery of rings 15 and l6,respe'ctively, are provided a'plurality of gear segments 27 and 28 engaging gears 29 add 30 journaled on stub shafts 31 and 32 secured, respectively, to the upper and lower faces of the vacuum box. Secured to, or formed integral with, gears 29 and 30 are cam cylinders 33 and 34 provided with inclined cam tracks 35 and 36 in which ride pins 37 and 37 secured respectively to members 12 and 13. As will be evident rotation of handwheel 26 operates through gears 22 and 23 gear segments 20-21, gear segments 27-28, and gears 29- 30 to rotate cam cylinders 33 and 34 to simultaneously move members 12 and 13 inwardly to close cavity 4.

The sheet of stock from which the tube is to be shaped is spliced into the form of an annular band 38 which is positionedlbe fore the cavity 4 as shown in Figure 2. For ease and quickness in positioning the band 38 I provide a table 39 mounted on a shaft 40 threaded into the base 1 as at 41 the split at 44 and provided with-a toggle 45 1 adapted to expand and contract the ring in an obvious manner. 'It will be understood that any suitable means may be provided for clamping the stock in position such as spring fingers secured to the members 12 and 13, or as suggested clamping means may be omitted entirely under suitable conditions.

. ,W'ith the stock positioned as shown in Figure 2 and the parts of the apparatus in the position shown in that figure, the valve 8 is operated to exhaust the air from chamher 6 causing the band of stock to be drawn I and stretched into cavity 4 and against the ing ortions 53 of the stock. Edge 54 of 111cm )el' 12 and shoulder 55 of member 13 are so proportioned that they do not completely meet when members 12 and 13 are in their innermost position, and are provided with points 56 which function to stitch the edges of the stock together to close the tube. If desired stitcher points 56 may be omitted and the edges of band 38 given a coating of cement prior to shaping or both the stitching and cement may be used.

For the purpose of: cutting a valve hole in the tube, I provide at any suitable point on the members 12 and 13 substantially semicircular dies-60 and 61, best shown in Figures 6 and 7. These dies cooperate to cut a circular hole in the base of the tube in the manner shown in the latter figure.

After members 12 and 13 have been moved together to'complete the formation of the tube asdescribed, these members. are separated, chamber 6 is vented tothe atmosphere by manipulating valve, 8, and the formed tube removed.

While I have shown mechanical means for moving members 12 and 13 together other g suitable means such as compressed air cylinders may be substituted if desired without departing from the spirit of my invention.

I claim:

1. A device of the character described comprising an annular vacuum chamber having a substantially U sha ed cavity communicating with the chamber and adapted on the creation of a vacuum in the chamber to draw a band of material, positioned across the mouth of the cavity, into contact with the fwalls of the latter, and means-operating across the mouth of the cavity adapted to join the edges of the band to form an annular tube. a a I 2. A device of, the character described comprising an annular vacuum chamber having a substantially 'U shaped cavity communicating with the chamber and adapted on the creation of a vacuum in the chamber to draw a band of material, positioned across the mouth of. the cavity into contact with the walls of the latter, opposed annular members movable towards each other across themouth of the cavity to join the edges of the band to complete the formation of the latter into an annular tube. V

3. A device of the character described comprising an annular vacuum chamber having a substantially U shaped cavity communicating with the chamber, cylindrical members normally positioned at either side of the mouth .of the cavity and means adapted to move saidmembers toward each other across the mouth of the cavity.

4. A device of the character described comprising an annular vacuum chamber having a substantially U shaped cavity communicating with the chamber, cylindrical members normally positioned at either side of the mouth of the cavity, means adapted to support a band of material across the mouth of the cavity and in position to be drawn into contact with the walls thereof upon the creation of a vacuum in the chamher and means to move the cylindrical members toward each other across the mouth of the cavity to join the edges of the band.

5. A device of the character described comprising an annular vacuum chamber havlng a substantially 'U shaped cavity communicating with the chamber, cylindrical members operating across the inner annular face of the chamber and normally positioned at either side of the cavity, means adapted to support a band of material across the mouth of the cavity in overlappin relation with the cylindrical members an in position to be drawn into contact with the walls of the cavity upon creation of a vacuum in the chamber and means to move the cy1indrical members toward each other across the mouth of the cavity to join the edges of the band.

6. A device of the character described comprising an annular vacuum chamber having a substantially U shaped cavity communicating with the chamber, cylindrical members operating across'the inner annular face of the chamber and normally ositioned at either side of the cavity, means or clamping the ed es of a band of material against said cylin rical members to hold the band in position to be drawn into contact with the walls of the cavity upon creation of a vacuum in the chamber and means to move the cylindrical members toward each other across the mouth of the cavity to join the ed es of the band.

A device of the character described comprising an annular vacuumchamber having a substantially U shaped cavity communicating with the chamber, members movable across the inner annular face of the chamber and normally positioned at either side of the cavity, adjustable means adapted to support a band of material across the mouth of the cavity in overlapping relation with said members, means to clamp the edges of the band against said members and nulushaving a substantial y U shaped'cross section, and bringing the edges of the U together to form an annular tube.

9. The method of'forming annular tubes which comprises forming an annular band of suitable stock, forcin the central portion of the band outwar ly to form an annulus having a substantially U shaped cross section-and bringing the edges of the U to gether in face to face relation to form an annular tube.

10. The method of forming annular tubes which comprises forming an annular band of suitable stock, forcing the central portion of the band outwardly to form an annulus having a substantially U shaped cross-section, bringing the edges of the U together in face tof ace relatlon and stitching the edges together. i i

In testimony whereof I have signed my name to the above specification.

GEORGE 'L. MATHER. 

